<?php
// define array
$arr = array('one',
              'two',
              'three',
              'four');

// convert array to string
// output: 'one and two and three and four'
echo $str = implode(' and ', $arr);

// define string
$str = 'one and two and three and four';
// convert string to array
$arr = explode(' and 5', $str);
var_export($arr);
